Demi Lovato's live singing in her new music promo proves she is the "real deal".

The director of the singer's Heart Attack video Chris Applebaum revealed that before Demi, the only other artist he'd seen sing live was Céline Dion.

In the just-released clip Demi shows her dark and light sides, but what she proved on set was even more impressive, Chris claimed.

"In 20 years of directing music videos, I have seen every single artist lip-sync to their video with the exception of two people. One was Céline Dion, who said, 'If you don't do that, you sing so that people can see your throat move and people can feel the emotion.' And two, it was Demi Lovato," he revealed to MTV News. "Demi is the real deal. People felt it when they were around her."

Chris added that Demi put on an explosive performance during their shoot. She was so convincing with her act that he was taken aback.

"Her performance is very interesting. I've worked with some of the biggest artists in the world, multiple times, and Demi is a really unique performer," he pondered. "She's extremely emotional. She's extremely complicated, wonderful, amazing, beautiful girl with a huge heart and conflicts within herself that she's dealing with very openly."

Chris went on to describe the concept behind the promo. He alluded that Demi is a complex character with many different sides to her personality.

"The song is about this kind of duality that Demi faces," he explained. "First you see Demi pictured in this more angelic white performance where these darker black elements start creeping into the frame almost ready to take over her. And then you also see her, the polar opposite, a black set-up where there's some white or good, I don't want to say good or evil, or good or bad, there's just sort of these opposites."

The 20-year-old singer recently told E! News that she was excited for her fans to hear her new album.

Heart Attack is the lead single from the record Demi, which is due for release on May 14.

“Fans can expect a less dancey-pop album. I’m trying to stay away from EDM on this album and no dubstep for me," she laughed.

“I miss hearing real instruments on the radio and I wanna be able to bring that back. That’s important to me. I want my sound and lyrics to mature as well as I have the past year.”